cluster_info detect recovery mode in version 12

Hello!

With postgresql-12 comes new standby/recovery management and recovery.conf file has been removed (source).

The pg_lsclusters command must be able to detect recovery mode.
https://salsa.debian.org/postgresql/postgresql-common/blob/master/PgCommon.pm#L666

The pg_controldata shows relevant state on a cluster data directory

sudo -u postgres /usr/lib/postgresql/12/bin/pg_controldata -D /var/lib/postgresql/12/lab1
...
Database cluster state:               in production
... (or)
Database cluster state:               in archive recovery

In a fast way, recovery.signal and standby.signal are good replacements in version 12. Best regards, Florent